Under the convention, vessels from other countries can fish off the UK coastline
Agriculture Minister Michael Creed says a decision by the British government to withdraw from a fisheries convention is "unwelcome and unhelpful".
The UK is pulling out of the 1964 London Fisheries Convention.
Minister Creed says: "Today's announcement by the UK Government is unwelcome and unhelpful. It is a part of Brexit and will be considered by the EU 27 MSs and the Barnier team when the negotiations commence.
"The announcement will have no immediate effect as the withdrawal process from the convention will take two years and will form part of the Brexit negotiations."
The convention grants rights to neighbouring countries to fish in each other's six to 12 mile fishing zones based on historic fishing activity.
The Irish fishing fleet has access to parts of the UK zone, as has the UK fleet to parts of the Irish zone.
These access rights were incorporated into the EU Common Fisheries Policy when Ireland joined the EU.
Minister Creed adds: "The threats posed by Brexit to the Irish fishing industry was discussed last Thursday with the Irish industry at a session of the SeaFest Conference in Galway.
"Brexit poses very serious challenges to the seafood sector and this announcement will form part of the negotiations."
British Environment Secretary Michael Gove said: "Leaving the London Fisheries Convention is an important moment as we take back control of our fishing policy.
"It means for the first time in more than 50 years we will be able to decide who can access our waters.
"This is an historic first step towards building a new domestic fishing policy as we leave the European Union - one which leads to a more competitive, profitable and sustainable industry for the whole of the UK."
The UK fishing industry was made up of more than 6,000 vessels in 2015, catching 708,000 tonnes of fish.
Some 10,000 tonnes of British fish were caught by other countries under the convention.